Whenever using a pronoun, it must refer to something previously mentioned in the sentence, paragraph, or story. For example, in the previous sentence, it refers to pronoun.

You’ll also notice that I used it rather than he or they. That’s because a pronoun also must agree with the number, gender and type of the word it refers to (The word referred to is called an antecedent). A pronoun isn’t a male but a genderless object, or an it. A pronoun also means a lone word not a plurality of them and so it (which is singular) is used rather than they (which means more than one).

Using the correct pronoun that refers to a word is called pronoun agreement.

Often in casual conversation, we’re a bit sloppy with agreement; that often is all right, as the listener who can hear inflections in a speaking voice usually knows what you mean – though if too sloppy, you can sound uneducated. In writing, however, lack of pronoun agreement really stands out, as it creates confusion. For example, Jane sat on the sofa while Alice poured her wine. Is Alice pouring wine for herself or for Jane? Or did the writer something entirely different, as in Jane sat on the sofa while Alice poured their wine? Simply put, by getting the agreement right, the reader can understand what you really mean.